Yeah, The highest return I have seen from binary options is around 86%.
Would it make you think that the site will be fairer if it used a regulated market index like the Nasdaq instead of the price of bitcoin in Bitfinex? It would be better, I reckon. Less suspicions of price manipulation.
No, it won't. You can never be sure about what's going on behind the scene.
In any case, asking for provably fair in the sense that it is free from manipulation is asking for the impossible.
Exactly! So I would rather gamble on something which is provable-fair than something which can't be free from manipulation.